tinygo/compiler/reflect.go

84 строки
2,2 КиБ
Go

package compiler
import (
"math/big"
"strings"
)
var basicTypes = map[string]int64{
"bool": 1,
"int": 2,
"int8": 3,
"int16": 4,
"int32": 5,
"int64": 6,
"uint": 7,
"uint8": 8,
"uint16": 9,
"uint32": 10,
"uint64": 11,
"uintptr": 12,
"float32": 13,
"float64": 14,
"complex64": 15,
"complex128": 16,
"string": 17,
"unsafeptr": 18,
}
func (c *Compiler) assignTypeCodes(typeSlice typeInfoSlice) {
fn := c.mod.NamedFunction("reflect.ValueOf")
if fn.IsNil() {
// reflect.ValueOf is never used, so we can use the most efficient
// encoding possible.
for i, t := range typeSlice {
t.num = uint64(i + 1)
}
return
}
// Assign typecodes the way the reflect package expects.
fallbackIndex := 1
for _, t := range typeSlice {
if t.name[:5] != "type:" {
panic("expected type name to start with 'type:'")
}
num := c.getTypeCodeNum(t.name[5:])
if num == nil {
// Fallback/unsupported types have a typecode with the lowest bits
// set to 11.
t.num = uint64(fallbackIndex<<2 | 3)
fallbackIndex++
continue
}
if num.BitLen() > c.uintptrType.IntTypeWidth() || !num.IsUint64() {
// TODO: support this in some way, using a side table for example.
// That's less efficient but better than not working at all.
// Particularly important on systems with 16-bit pointers (e.g.
// AVR).
panic("compiler: could not store type code number inside interface type code")
}
t.num = num.Uint64()
}
}
// getTypeCodeNum returns the typecode for a given type as expected by the
// reflect package. Also see getTypeCodeName, which serializes types to a string
// based on a types.Type value for this function.
func (c *Compiler) getTypeCodeNum(name string) *big.Int {
if strings.HasPrefix(name, "basic:") {
// Basic types have a typecode with the lowest bits set to 00.
num, ok := basicTypes[name[len("basic:"):]]
if !ok {
panic("invalid basic type: " + name)
}
return big.NewInt(num<<2 | 0)
} else if strings.HasPrefix(name, "slice:") {
// Slices have a typecode with the lowest bits set to 01.
num := c.getTypeCodeNum(name[len("slice:"):])
num.Lsh(num, 2).Or(num, big.NewInt(1))
return num
} else {
return nil
}
}